JPH0380255A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve chemical durability, electrical durability, cleanability and mechanical durability by forming a photosensitive layer contg. a binding resin made of specified fluorine-contg. polyester. CONSTITUTION:A photosensitive layer contg. a binding resin made of fluorine- contg. polyester based on repeating units represented by formulae I, II is formed. In the formulae I, II, X is -O-, -CO-O-, -CO-NH- or -CO-, r is 0 or 1, R<1> is F substd. 1-20C alkyl, R<2> is a divalent arom. group, R<3> is a divalent org. residue and the molar ratio of m/n is 1/99-100/0. Chemical durability, electrical durability, cleanability and mechanical durability can be simultaneously improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having an improved photosensitive layer.

[Prior Art] Conventional electrophotographic photoreceptors include those that use a laminated photosensitive layer in which a charge generation material that generates charges and a charge transfer material that transfers charges are separated into each layer, and those that use a laminated photosensitive layer that has a structure in which a charge generation substance that generates charges and a charge transfer substance that transfers charges are separated in each layer. A photoreceptor using a single-layer photoreceptor layer containing the above-mentioned photoreceptors has been proposed. These photosensitive layers are formed by dispersing or dissolving the substance in a binder resin.

When such an electrophotographic photoreceptor is applied to a conventional electrophotographic process such as the Carlson method, various problems occur. For example, there has been a drawback that the charge transfer substance has poor compatibility with the binder resin, which causes the charge transfer substance to crystallize or deteriorate over time. In addition, for example, in the case of a photoreceptor with a charge transfer layer formed on the surface layer consisting of a charge transfer substance and a binder resin, wear and tear due to adhesion of toner to the surface of the photoreceptor layer and contact between the developer and transfer paper and the surface of the photoreceptor layer may occur. It had the disadvantage of causing scratches.

Polycarbonate, polyester, polymethyl methacrylate, and the like have been proposed as binder resins for photosensitive layers that solve these problems.

[Problems to be Solved by the Invention] However, even when these binder resins are used, the above-mentioned drawbacks cannot be sufficiently solved.

Further, although it has been proposed to provide a protective layer on the photosensitive layer, the above-mentioned drawbacks cannot be satisfactorily solved as long as the above-mentioned resin is used as the binder resin for the protective layer.

The present invention was made in view of the problems in the prior art as described above, and its purpose is to improve chemical durability such as improving compatibility with charge transfer agents, and electrical durability such as electrophotographic sensitivity. The object of the present invention is to provide an electrophotographic photoreceptor that simultaneously has cleaning properties such as toner cleaning properties and toner filming properties, and mechanical durability such as abrasion resistance and scratch resistance.

[Means to solve the problem] In order to achieve the above object, the present invention has the following configuration.

(1) An electrophotographic photoreceptor comprising at least a conductive support and a photosensitive layer, in which the photosensitive layer contains a repeating unit represented by the following general formula (I) and a repeating unit represented by the following general formula (II). -Co-0-, -Co-NH-
, and -CO-, and r represents 0 or 1. R1 represents an alkyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom or an alkenyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom. R2 represents a divalent aromatic group. R3 represents a divalent organic residue. m/
The molar ratio of n is 1/99 to 10010. ) In the present invention, R1 represents an alkyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom or an alkenyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom. The number of carbon atoms in R1 is preferably 2 or more, more preferably 3 to 1, from the viewpoint of the reactivity of the dicarboxylic acid that is the starting material of the polyester, toner filming property, toner cleaning property, etc.
It is 5. The number of fluorine atoms substituted in R1 is preferably 2 or more from the viewpoint of toner filming properties and toner cleaning properties, and more preferably an alkyl group having 3 or more carbon atoms or an alkenyl group having 3 or more carbon atoms as R1. The number of fluorine atoms is particularly preferably 5 or more. Further, from the viewpoint of exhibiting high toner filming properties and toner cleaning properties, it is preferable that the terminal of the alkyl group or alkenyl group is fluorinated.

R1 may be linear or branched. Specific examples where R1 is a straight chain include a methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n- heptyl group,
Examples include n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, and n-dodecyl group.

Specific examples where R1 is branched include isopropyl group, isobutyl group, 5ee-butyl group, tert-butyl group, 1-methylbutyl group, 2-methylbutyl group, 3 substituted with at least one fluorine atom, -Methylbutyl group, 1,1-dimethylpropyl group, ■, 2-dimethylpropyl group, 2゜2-dimethylpropyl group, 1-ethyl-
2-methyl-1-propenyl group, 2-isopropyl-1
Examples include 3-dimethyl-1-butenyl group.

A polyester having a repeating unit represented by the above general formula (I) can be produced from a dicarboxylic acid civalide represented by the following general formula (III) and a diol represented by the following general formula (V).

Polyesters containing repeating units represented by the above general formulas (I) and (n) as main components are the following general formulas (DI
) and (rV), and dicarboxylic acid cybalide represented by the following general formula (V) (wherein X, r, R'' are
It is the same as general formula (I), and 2 is a halogen group. ) Z-Co-R3-Go-Z (IV) (in the formula, R3 is the same as in general formula (n), and Z is a)logen group.

HO-R2-OH(V) (In the formula, R2 is the same as in general formula (I).) As a method for producing dicarboxylic acid cybaride represented by the above general formula (m), a dicarboxybenzene derivative and at least A compound represented by the following general formula (VI) is synthesized by reaction with a compound containing an alkyl group or an alkenyl group substituted with one fluorine atom. or,
After reacting a xylene derivative with a compound containing an alkyl group or an alkenyl group substituted with at least one fluorine atom, the following method is used to convert two methyl groups bonded to a benzene ring into carboxyl groups using a conventionally known oxidizing agent. A compound represented by general formula (VI) is synthesized. Next, the obtained compound (VI) is halogenated with various conventionally known carboxylic acids (in the formula, X, r, R'' are the same as in the general formula (I)) represented by the above general formula (Vl) Examples of dicarboxylic acids include dicarboxybenzene fluoroalkyl ether,
Examples include fluoroalkyl dicarboxybenzoate, N-fluoroalkyldicarboxybenzamide, dicarboxybenzenefluoroalkyl ketone, and dicarboxyfluoroalkylbenzene.

Examples of the dicarboxylic acid civalide represented by the above general formula (IV) include the following dichlorides of dicarboxylic acids,
Examples include difluoride and dibromide. Namely, terephthalic acid, tetrafluoroterephthalic acid, isophthalic acid, tetrafluoroisophthalic acid, naphthalene dicarboxylic acid, 4. Examples include dichloride, difluoride, and dipromide such as 4'-diphenyl ether dicarboxylic acid, oxalic acid, succinic acid, adipic acid, and sebacic acid.

When these dicarboxylic acid halides are used as a mixture, by containing 5 mol percent or more of the dicarboxylic acid halide represented by the general formula (I [[), the toner filming property, which is one of the characteristics of the present invention, Cleanability can be sufficiently improved.

In the above general formula (V), R2 which is a divalent aromatic group
In particular, mono- to tetra-nuclear bodies are desirable. Specific examples include catechols, resorcinols, hydroquinones, dihydroxybiphenyls, and bis(hydroxyphenyl)ethanes.

In the present invention, it is also possible to use a mixture of aliphatic diols in part with these aromatic diols. Examples of diols that can be used include ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, and cyclohexane dimetatool.

When a mixture of these aliphatic diols is used, by containing 70 mol percent or more of the aromatic diol, the glass transition temperature can be sufficiently raised and the mechanical durability can be improved.

From the viewpoint of mechanical durability, the preferred molecular weight is in the range of 0.1 to 2.0 dl/g, more preferably in the range of 0.2 to 1.5 dl/g in terms of intrinsic viscosity. preferable.

In the present invention, 100 to 1 mol% of the dicarboxylic acid civalide (III) above is used, and the remaining 0 to 99 mol%
By using the dicarboxylic acid cybalide of the above general formula (IV) and reacting them with the diol represented by the above general formula (V), a compound consisting of the above general formulas (I) and (II), with m / n Molar ratio tel OOlo = 1/9
A polyester of 9 parts is produced.

In order to sufficiently improve toner cleaning properties and toner filming properties, the m/n molar ratio is preferably 1/99 or more, and more preferably 5/95 or more.

The polyester resin of the present invention has sufficient strength and flexibility as a binder resin for the photosensitive layer of an electrophotographic photoreceptor.

This applies not only to electrophotographic photoreceptors that have a photosensitive layer formed on a non-flexible cylindrical substrate, but also to electrophotographic photoreceptors that have a photosensitive layer formed on a flexible sheet or belt-like substrate. Very suitable as a binding resin for the body.

Furthermore, the polyester resin of the present invention has low surface energy, a large surface contact angle, and good slipperiness. When a layer containing this resin is formed on the surface layer, it is possible to reduce the occurrence of toner filming, in which toner adheres to the surface of the photoreceptor, and also to reduce the occurrence of scratches on the surface. Since it has good sliding properties with toner and transfer paper, there is less wear on the photoreceptor, and as a result, the life of the photoreceptor can be extended.

Furthermore, the polyester resin of the present invention has excellent compatibility with charge transfer substances, and since it contains fluorine in its molecules, its relative permittivity is smaller than that of polyesters that do not contain fluorine in its molecules. As a result of these effects, large carrier mobility can be obtained, so that an electrophotographic photoreceptor having high sensitivity and high-speed response can be obtained.

In the present invention, known conductive supports can be used as they are. For example, conductive substances such as metals or metal oxides are deposited on plates, foils, or cylinders of metals or alloys such as aluminum or stainless steel, or plastic films, plates, or cylinders, or Examples include sheet-like, belt-like, and cylindrical products coated with oxide powder dispersed in resin.

In the present invention, the photosensitive layer may be of a laminated type in which a charge generation substance and a charge transfer substance are separated into each layer, or a single layer type in which a charge generation substance and a charge transfer substance are contained in the same layer.

In the present invention, known charge generating substances can be used as they are. Examples of inorganic charge generating substances include selenium, selenium tellurium, selenium tellurium, cadmium-selenium sulfide, and cadmium sulfide.

Organic charge-generating substances include azo-based substances such as monoazo, bisazo, and trisazo, phthalocyanine-based substances such as metal-free phthalocyanine and metal phthalocyanine, polycyclic non-based substances such as anthanthrone, perylene-based pigments, and squarylium-based pigments. Examples include dyes.

These charge generating substances can be used in combination with various resins and sensitizers, if necessary.

When the photosensitive layer in the present invention has a layer structure in which a charge generation layer and a charge transfer layer are laminated, the resin forming the charge generation layer may include polyamide, polyurethane, polycarbonate, polyvinyl butyral, polyvinyl, etc., in addition to the polyester of the present invention. Examples include formal, cellulose acetate-butyrate, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer, and vinyl acetate-vinyl chloride-maleic acid copolymer.

The charge generation layer can be obtained by vapor depositing the above charge generation substance or by applying and drying a coating liquid in which the above charge generation substance and a binder resin are dispersed or dissolved in a solvent.

In the present invention, known charge transfer substances can be used. Examples include pyrazoline derivatives, hydrazone derivatives, stilbene derivatives, oxazole derivatives, oxadiazole derivatives, and carbazole derivatives.

The charge transfer layer can be obtained by coating and drying a coating liquid in which these charge transfer substances are dissolved together with a binder resin.

When a charge transfer layer is formed on the surface layer, it is effective to use the polyester of the present invention as a binder resin for the charge transfer layer.

In the electrophotographic photoreceptor of the present invention, when the photosensitive layer has a layer structure in which a charge generation layer and a charge transfer layer are laminated, the charge generation layer and the charge transfer layer are not clearly separated, and the charge generation region The composition may change continuously from the charge transfer region to the charge transfer region.

Further, the charge transfer layer may be formed of two or more layers having different compositions. In this case, an effect can be expected if the polyester of the present invention is used as the binder resin for at least one layer, but it is more effective to use the polyester of the present invention as the binder resin for the surface layer. The composition of the charge transfer layer in the thickness direction may not be clearly separated and may vary continuously.

Further, when a charge generation layer is provided as an upper layer, it can be used as a positively charged type, and when a charge transfer layer is provided as an upper layer, it can be used as a negatively charged type. When the charge generation layer is formed on the surface layer, it is effective to use the polyester of the present invention as a binder resin for the charge generation layer.

Next, a method for manufacturing the electrophotographic photoreceptor of the present invention will be explained.

In the case of a laminated photoreceptor, the method for forming the charge generation layer is as follows:
A method of forming a charge generating substance on a substrate by a vacuum evaporation method, a sputtering method, a plasma CVD method, etc., or dispersing or dissolving the charge generating substance in a binder resin solution,
An appropriate method can be used, such as a method of coating and drying the coating on the substrate by a dip coating method, a roller coating method, a blade coating method, a spray coating method, or the like. The thickness of the charge generation layer is preferably 0.01 to 10 μm,
More preferably, it is 0.05 to 3 μm. When the charge generation layer is composed of a charge generation substance and a binder resin, the composition of the charge generation substance and the binder resin is 115 to 5/2.
The weight ratio is preferably 1/1, more preferably 1/
A weight ratio of 3 to 3/1 is desirable.

The charge transfer layer may be formed by dissolving the charge transfer substance and the binder resin in a solvent, applying the solution using the coating method described above, and drying the solution. The thickness of the charge transport layer is usually 5 to 50 μm1
More preferably, it is 10 to 30 μm. The ratio of charge transfer substance to binder resin is 20/100 to 20
The weight ratio is preferably 0/100, more preferably 60/100 to 130/100.

In the case of a single layer type, the charge generating substance, the charge transfer substance and the binder resin, or the charge generating substance and the binder resin are dissolved in a solvent.
It can be formed by applying and drying a dispersed coating liquid. The thickness of the photosensitive layer is preferably 5 to 100 μm, more preferably 10 to 50 μm. The composition of the charge generating substance, the charge transporting substance and the binder resin is preferably in a weight ratio of 1 to 20010 to 200/100.

When forming an insulating or conductive protective layer, the resin and, if necessary, additives may be dissolved in a solvent, applied by the above-mentioned coating method, and dried.

[Method for measuring properties] Electrophotographic properties were measured using an electrostatic copying paper tester EPA-8100 (
(manufactured by Kawaguchi Electric). Sensitivity was expressed as the amount of exposure required to reduce the surface potential by half.

The printing test was conducted using a partially modified commercially available printer. Scratches on the photoreceptor and toner filming properties were determined by visual observation and microscopic observation.

Surface contact angle was also measured as an index of toner cleaning properties, toner filming properties, slipperiness, etc.

In order to fully exhibit toner cleaning properties, toner filming properties, and ease of slipping, it is desirable that the surface contact angle is 85 degrees or more.

The surface contact angle is measured using a surface contact angle meter (Kyowa Interface Science).
The measurement was carried out using a commercially available product (Model CA-D, manufactured by Komatsu, Ltd.), and water was used as the measurement liquid.

The flexibility of the coating film was obtained by wrapping a photosensitive layer on a polyester film (manufactured by Toshi ■) around cylinders of various diameters.
A tension of 500 g/cm was applied and judgment was made based on whether or not cracks were generated in the coating film.

[Example] The present invention will be specifically described below based on Examples.

Synthesis Example 1 Add 0.0ml to 5.1ml of LM-NaOH aqueous solution. 57g
(2.5 mmol) of 2,2-bis(4-hydroxyphenyl)propane and (2) 5 mg of benzyltriethylene ammonium chloride were dissolved. In addition to this, 5. Q
0,32 g (0,5
m mol) of 5-[[3,4,4,4-tetrafluoro-2-[1°2.2,2. -tetrafluoro-1-
(Trifluoromethyl)ethyl-1,3-bis(trifluoromethyl)-1-butenyl]oxy]isophthaloyl dichloride, 0.15 g (0.75 mm.

l) isophthaloyl dichloride, 0.38 g (1,2
A mixture of 5 m mo 1) of terephthaloyl dichloride was added at once and stirred at 10°C for 30 minutes. The reaction solution,
The mixture was poured into 300 ml of boiling water to which a small amount of hydrochloric acid had been added to obtain a white flaky polymer.

Yield: 97% Intrinsic viscosity: 0.83 dl/g (in 1,1,2,2-tetrachloroethane, 25°C, 0
．． Measured at a concentration of 5g/dl) Synthesis Example 2 5.1ml of LM-NaOH aqueous solution was mixed with 0.0ml of LM-NaOH aqueous solution. 57g
(2.5 mmol) of 2,2-bis(4-hydroxyphenyl)propane and 15 mg of benzyltriethylene ammonium chloride were dissolved. In addition to this, 5.
0,19g (0,19g) dissolved in Oml dichloromethane
5 m mol) of 5-hebutafluoropentyl isophthaloyl dichloride, 0.15 g (0.75 m m
ol) isophthaloyl dichloride, 0.38 g (1
,25mm.

The mixture of terephthaloyl dichloride from 1) was added all at once and stirred at 10°C for 30 minutes. The reaction solution was poured into 300 ml of boiling water to which a small amount of hydrochloric acid had been added to obtain a white flaky polymer.

Yield: 97% Intrinsic viscosity: 0.84 dl/g (in 1,1,2,2-tetrachloroethane, 25°C, 0
．． Measured at a concentration of 5 g/di) Synthesis Example 3 0.57 g (
2,5 mmol) of 2,2-bis(4-hydroxyphenyl)propane and 15 mg of benzyltriethylene ammonium chloride were dissolved. In addition to this, 5. Om
0,875 g (2,
5m mol) c7) 5-Heptafluoropropyloxyisophthaloyl dichloride was added, and the mixture was stirred at 10°C for 30 minutes. The reaction solution was poured into 300 ml of boiling water to which a small amount of hydrochloric acid was added to obtain a white flaky polymer.

Yield: 97% Intrinsic viscosity: 0.81 dl/g (in 1,1,2,2-tetrachloroethane, 25°C, 0
．． Example 1 Polyvinyl butyral resin (“Eslec” BL-1,
5 parts by weight (manufactured by Tanemizu Kagaku Kogyo ■) were dissolved in 90 parts by weight of cyclohexanone, 5 parts by weight of titanyl phthalocyanine as a charge generating substance was mixed with this solution, and after being dispersed in a paint shaker for 3 hours, further cyclohexanone was added. Prepare a charge generation layer coating solution and apply it to an aluminum vapor-deposited film (
Coated on “Metal Me” (manufactured by Toshi ■) and dried to a film thickness of 0°2.
A charge generation layer of .mu.m was formed.

As a binder resin, polyester 10 obtained in Synthesis Example 1
Part by weight was dissolved in 90 parts by weight of 1,2-dichloroethane, and then 10 parts by weight of a compound represented by formula (■) as a charge transfer substance was added and dissolved to prepare a charge transfer layer coating solution. A charge transfer layer having a thickness of 20 μm was formed by coating and drying to obtain an electrophotographic photoreceptor.

Example 2 In Example 1-, titanyl phthalocyanine was converted to the formula (■
An electrophotographic photoreceptor was obtained in the same manner except that the bisazo pigment shown in ) was used.

Example 3 An electrophotographic photoreceptor was obtained in the same manner as in Example 1 except that the charge transfer substance was changed to a compound represented by formula (IX).

Example 4 An electrophotographic photoreceptor was obtained in the same manner as in Example 2 except that the charge transfer substance was changed to the compound used in Example 3.

Examples 5 to 8 Examples 5 to 8 were obtained in the same manner as Examples 1 to 4 except that the binder resin was changed to the polyester obtained in Synthesis Example 2.

Examples 9 to 12 Examples 9 to 12 were obtained in the same manner as Examples 1 to 4 except that the binder resin was changed to the polyester obtained in Synthesis Example 3.

Comparative Example 1 In Example 1, the binder resin of the charge transfer layer was polycarbonate (“Panlite” L-1225, manufactured by Kijin Kasei ■)
An electrophotographic photoreceptor was obtained in the same manner except that the following was changed.

Comparative Example 2 In Example 1, the binder resin of the charge transport layer was polymethyl methacrylate (“Acrivet” MD).

An electrophotographic photoreceptor was obtained in the same manner except that the material was changed to (manufactured by Mitsubishi Rayon ■).

Comparative Example 3 An electrophotographic photoreceptor was obtained in the same manner as in Example 1 except that the binder resin of the charge transfer layer was changed to polyarylate ("U Polymer" U-100, manufactured by Unitika Corporation).

Table 1 shows the results of measuring the compatibility between the charge transfer substance and the binder resin, flexibility, surface contact angle, and electrophotographic sensitivity of the samples of Examples 1 to 12 and Comparative Examples 1 to 3.

Example 13 4 parts by weight of copolymerized nylon ("Amilan" 0M8000, manufactured by Toshi ■) was dissolved in 96 parts by weight of methanol, and this solution was applied onto an aluminum tube by dip coating method, dried,
Film thickness 0. A 3 μm subbing layer was formed. Next, Example 1
The charge generation layer coating solution prepared above was applied onto the subbing layer by dip coating and dried to form a charge generation layer with a thickness of 0.2 μm.

Next, the charge transfer layer coating solution prepared in Example ↑ was applied onto the charge generation layer by dip coating and dried to give a film thickness of 20 μm.
A charge transfer layer was formed to obtain an electrophotographic photoreceptor.

Comparative Example 4 An electrophotographic photoreceptor was obtained in the same manner as in Example 13 except that the charge transfer layer coating liquid was changed to that used in Comparative Example 3.

After the photoreceptors obtained in Example 13 and Comparative Example 4 were installed in a commercially available modified printer and a 10,000-sheet printing test was performed,
Table 2 shows the results of an investigation of scratches on the photoconductor, toner filming state, and scumming state of printed matter.

[Effects of the Invention] The present invention provides an electrophotographic photosensitive material that has cleaning properties such as chemical durability, electrical durability, toner cleaning property and toner filming property, and mechanical durability such as abrasion resistance and scratch resistance. I was able to donate my body.

Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 1O Example 11 Example 12 Comparative example 1 Comparative example 2 Comparative example 3 surface contact angle 05 05 03 03 8 8 4 4 06 06 06 06 8 6 4 Example 13 Photoreceptor scratches none Table 2 toner filming none Comparative example 4 can be can be (Every time) Electrophotographic sensitivity (μJ/cm2) 0.30 0.30 0.42 0.42 0.32 0.32 0.42 0.42 0.30 0.30 0.40 0.40 0.44 〉5 0.48 Scratches on printed matter none slightly

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor comprising at least a conductive support and a photosensitive layer, the photosensitive layer mainly contains repeating units represented by the following general formula (I) and repeating units represented by the following general formula (II). An electrophotographic photoreceptor comprising a binder resin made of fluorine-containing polyester as a component. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In general formulas (I) and (II), X is -O-,
At least one member selected from the group of -CO-O-, -CO-NH-, and -CO-, and r represents 0 or 1. R^1 represents an alkyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom or an alkenyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom. R^2 represents a divalent aromatic group. R^3 represents a divalent organic residue. The molar ratio of m/n is 1/
It is 99-100/0. )